Eur. Phys. J. B 21, 75-80 (2001)
https://doi.org/10.1007/s100510170215

Josephson effect through a ferromagnetic layer

¹ Centre de Recherche sur les Très Basses Températures (CRTBT-CNRS), Université Joseph Fourier, BP 166, 38042 Grenoble Cedex 9, France
² Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse CNRS-IN2P3, Université Paris Sud, bâtiment 108, 91405 Orsay, France

Corresponding author: ^a gandit@labs.ploycnrs-gre.fr

Received: 20 September 2000
Revised: 22 February 2001
Published online: 15 May 2001

Abstract

We report transport measurements on Superconductor/Ferromagnet/Superconductor (S/F/S) junctions: Nb/Al/Gd/Al/Nb where gadolinium (Gd) is a weakly polarized ferromagnet. A sizeable critical current I_c is observed in the I(V) characteristics. This current can be modulated by a weak magnetic field, as expected for a Josephson current. With these experiments, we establish that superconducting coherent transport survives across a small ferromagnetic layer. The penetration depth of Cooper pairs in Gd has been measured. An extensive study of the Josephson critical current in temperature for different thicknesses of magnetic compounds is presented. A comparison of transport measurements with S/N/S junction is given through measurements made on Nb/Al/Y/Al/Nb, where yttrium (Y) is used as non magnetic rare earth metal.